Hey to you all, been awhile since I posted, but good to be back. I wanna know if a '79 sporty swingarm and front end will fit on a sporty '70 frame? I have a '70 sporty partial bike(with engine) and can get '79 partial bike(without engine). The '70 has drum brake setup, the '79 has disc setup. I plan on making this just a "bar-hopper". I'd rather have disc brakes which is why I posted this question. I'm sure I can rigg up a master/cyl. and anything else needed. The shocks, If I had to, I'll put on struts and make it a hardtail. Please comment. Thanks

Last edited by buddha on Sun May 24, 2009 12:39 pm, edited 1 time in total.

IIRC, the 79s used tapered Timken bearings in the neck, instead of loose ball bearings. I would imagine if you switched the neck cups, you could use the forks. The square swing arm has a different location for the shocks, I don't remember about the pivot bearings. Just having a front disc would be a big improvement over drum brakes.VPH-D

VPH-D wrote:Just having a front disc would be a big improvement over drum brakes.VPH-D

Theoretically it should be, yes; however the early single discs were pretty poor, wouldn't stop a clock! Later twin disc set-up was a bit better but best results (inevitably!) come from fitting aftermarket calipers; Brembo ones are a good choice, powerful but not bulky so they don't spoil the bike's looks.

I've often played with the idea of converting my 72's front brake to hydraulic operation, or even twin leading shoe. Anyone ever come across this?

Yeah just like every one else said 79 is a bastard year (frame, ignition, other little stuff) but with the later style bearing cups th front end should fit. As far as the ass end I'd look for a swing arm set up from ebay or just hardtail the 70 frame, but definatly not use struts

Willy:If you just want to cross stuff over without doing any work you maybe should keep to close years. There was not that much that was incompatable between all the sporty years. The 79 front end will fit on the earlier bike. It would be best to knock the bearing cups out and change then over. It might be an opportunity to install a chrome set of timken cups. Pretty easy swap. The swingarm will fit. I think both swingarms are timken. It's pretty easy to relocate shock mounts or to find different lengths of shocks. I'd say using the shocks from the 79 would be a proper fit. The top mounts didn't change if I remember right. This swap should be fairly easy if you just think it out.